I am afraid of how I will be treated in Seoul?

From this I'm guessing you're American :P I'm not gonna lie, they'll definitely notice you, but most won't be unfriendly to you. Keep in mind though that Koreans are extremely proud and nationalistic. Just show how much you respect their culture and that should be enough :) You'll probably have an easier time than I would actually; most of the koreans I know are super awesome but a few of them do carry an air of superiority around me or other chinese people :/